Mobile communications terminal, service area calculation apparatus and method of calculating service area

ABSTRACT

A mobile communications terminal includes positional information generator configured to generate positional information indicating a current position of the terminal, receiver which receives identification information sent from the base station of the second mobile communication network, notification information generator configured to generate notification information including the identification information and the positional information generated at the time of receiving the identification information, and transmitter which transmits the notification information to the service area calculation apparatus via the first mobile communication network to derive the information concerning the service area.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based upon and claims the benefit of priorityfrom the prior Japanese Patent Application No. 2002-366906, filed Dec.18, 2002, the entire contents of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a mobile communicationsterminal, a service area calculation apparatus which calculates aservice area of a mobile communications network, and a method ofcalculating the service area.

[0004] 2. Description of the Related Art

[0005] As wireless LANs (local area network) have recently becomecommon, various providers provide mobile communications services invarious spots.

[0006] Such mobile communications services generally use a wirelesscommunication method. Therefore, if a user makes a contract with serviceproviders, he/she can be provided with various services anytime andanywhere with one mobile communications terminal.

[0007] However, service areas of the mobile communications servicesmentioned above are discretely formed. It is thus difficult for the userto know where the service areas are located.

[0008] In addition, in a method disclosed in the patent document (Jpn.Pat. Appln. KOKAI Publication No. 2002-223218), an address (MAC address)unique to a wireless terminal, positional information thereof and acommunication quality concerned with the position are stored so as toform a plane view that tells whether or not the communication quality isgood in a plane where the wireless terminal can be disposed.

[0009] Under the circumstances described above, it is desired that thevarious service areas should be generally grasp.

[0010] In the Patent document described above, it is found out whetheror not the communication quality is good in a plane where the wirelessterminal can be located, for example, based on a communication state inthe wireless terminal. It can not be applied to grasp of the respectiveservice areas that belong to a plurality of mobile communicationsnetworks.

[0011] In other words, the Patent document described above, does notallow the service area of the mobile communications network to be graspby a third party except for its operator. Therefore, it is difficult tograsp conditions of a plurality of service areas formed by variousoperators at their discretion.

BRIEF SUMMARY OF THE INVENTION

[0012] The present invention has been attained in consideration of suchcircumstances, and its object is to allow a service area of a mobilecommunications network to be grasp even by those who are not itsoperators.

[0013] According to an aspect of the present invention, there isprovided a mobile communications terminal adapted to communicate with aservice area calculation apparatus via a first mobile communicationnetwork, the service area calculation apparatus collecting andtransmitting information concerning a service area provided by the firstmobile communication network and a second mobile communication networkincluding a base station, the mobile communications terminal comprising:a positional information generator configured to generate positionalinformation indicating a current position of the terminal; a receiverwhich receives identification information sent from the base station ofthe second mobile communication network; a notification informationgenerator configured to generate notification information including theidentification information and the positional information generated atthe time of receiving the identification information; and a transmitterwhich transmits the notification information to the service areacalculation apparatus via the first mobile communication network toderive the information concerning the service area.

[0014] According to another aspect of the present invention, there isprovided a service area calculation apparatus comprising: a receiverwhich receives the notification information transmitted from the mobilecommunications terminal according to claim 1 via the first mobilecommunication network; a storage device which stores a table indicatingthe positional information and the identification information associatedwith each other; and a calculation device configured to calculate aservice area of the base station indicated by the identificationinformation based on a distribution of a position indicated by thepositional information in correspondence with the identificationinformation referring to the table.

[0015] According to yet another aspect of the present invention, thereis provided a method of calculating a service area, comprising:receiving notification information including identification informationof a base station and positional information of the mobilecommunications terminal, the notification information being sent fromthe mobile communications terminal via a mobile communications network;storing a table indicating the identification information and thepositional information included in the received notification informationand corresponding to the identification information; examining adistribution of positions indicated by the positional information foreach piece of identification information referring to the table; andcalculating a service area of the base station indicated by theidentification information based on the distribution.

[0016] Additional objects and advantages of the invention will be setforth in the description which follows, and in part will be obvious fromthe description, or may be learned by practice of the invention. Theobjects and advantages of the invention may be realized and obtained bymeans of the instrumentalities and combinations particularly pointed outhereinafter.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0017]FIG. 1 is a block diagram showing a structure of a wirelesscommunication system according to a embodiment of the present invention;

[0018]FIG. 2 is a block diagram showing a structure of a mobilecommunications terminal MT;

[0019]FIG. 3 is a block diagram showing a structure of a serviceprovider control station CS10;

[0020]FIG. 4 is a flowchart showing a procedure of base stationdetection process in the mobile communications terminal MT;

[0021]FIG. 5 is a block diagram showing how the mobile communicationsterminal MT obtains the base station identification information andsends the notification information including the base stationidentification information to the service provider control station CS10;

[0022]FIG. 6 is a flowchart showing a procedure of base stationinformation storing process in the service provider control stationCS10;

[0023]FIG. 7 is a diagram showing stored information of the base stationinformation table 24 a;

[0024]FIG. 8 is a flowchart showing a procedure of service areacalculation process;

[0025]FIG. 9 is a view showing a specific example of service areacalculation;

[0026]FIG. 10 is a view showing how the service area is recalculated;

[0027]FIG. 11 is a flowchart showing a procedure of area informationproviding process;

[0028]FIG. 12 is a view showing a stored information of the servicecontents table 24 c;

[0029] The accompanying drawings, which are incorporated in andconstitute a part of the specification, illustrate presently preferredembodiments of the invention, and together with the general descriptiongiven above and the detailed description of the preferred embodimentsgiven below, serve to explain the principles of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0030]FIG. 1 is a block diagram showing a wireless communication systemaccording to the present embodiment.

[0031] First to third networks NW1, NW2 and NW3 are mobilecommunications networks respectively provided by different providers.Base stations BS1 to BS3 are connected to the first to third networksNW1 to NW3. The base stations BS1 to BS3 respectively form service areasSA1 to SA3.

[0032] Furthermore, the base stations BS1 to BS3 perform a wirelesscommunication with mobile communications terminals MT located withintheir service areas SA1 to SA3 so as to allow the mobile communicationsterminals MT to communicate via their networks. It should be noted thatthe service area SA1 is wider than the service areas SA2 and SA3. Theservice areas SA2 and SA3 exist within the extent of the service areaSA1. The first to third networks NW1 to NW3 are connected to a fourthnetwork NW4 via their control stations CS1 to CS3. A cellular systemmobile communications network such as a mobile telephone network isassumed as the first network NW1, for example. Spot area services by awireless LAN are assumed as the second and third networks NW2 and NW3,for example. The Internet is assumed as the fourth network NW4, forexample. Generally, the first network NW1 provides a low transmissionrate despite its wide service area and high mobility. The second andthird networks NW2 and NW3 provide a high transmission rate despitetheir narrow service areas and low mobility.

[0033] It should be noted that the base station BS1 is connected to thefirst network NW1, but this is not shown in FIG. 1. Similarly, the basestation BS2 is connected to the second network NW2, and the base stationBS3 is connected to the third network NW3. These base stations BS1 toBS3 thus form the service areas SA1 to SA3, respectively.

[0034] The mobile communications terminals MT can optionally utilize thefirst to third networks NW1 to NW3 to communicate.

[0035] A service provider control station CS10 is connected to thefourth network NW4. A service area calculation apparatus according tothe present invention is applied to the service provider control stationCS10, which collects and distributes information on the service areasprovided by the second and third networks NW2 and NW3.

[0036]FIG. 2 is a block diagram of the mobile communications terminalMT.

[0037] As shown in FIG. 2, the mobile communications terminal MTincludes antennas 11, 12 and 13, a first transceiver 14, a secondtransceiver 15, a global positioning system (hereinafter referred to asGPS) receiver 16, an input/output section 17, a timer 18 and a processor19.

[0038] The first transceiver 14 performs a wireless communication withthe base station BS1 via the antenna 11. The second transceiver 15performs a wireless communication with the base stations BS2 and BS3 viathe antenna 12. The GPS receiver 16 receives a GPS signal via theantenna 13. The GPS receiver 16 generates positional informationindicating a current position of the mobile communications terminal MTbased on the received GPS signal.

[0039] The input/output section 17 includes a display, a key button, amicrophone or a speaker, and performs various kinds of input/outputoperations such as input of user operations and input/output of voices.The input/output section 17 may be individually provided with thevarious kinds of devices mentioned above or may be configured byintegrating these devices in one unit.

[0040] The timer 18 generates date and time information indicating thecurrent date and time.

[0041] The processor 19 is configured by use of a microprocessor, forexample. The processor 19 performs various kinds of processing forgenerally managing the mobile communications terminals MT. The processor19 comprises a base station detector 19 a in addition to a function ofperforming known processing for achieving various functions that themobile communications terminal MT comprises. The base station detector19 a utilizes the second transceiver 15 to obtain base stationidentification information on the base stations belonging to thenetworks other than the first network NW1.

[0042] This base station identification information is the informationuniquely added to each base station.

[0043] The base station detector 19 a generates notification informationin which the positional information and the date and time informationgenerated by the GPS receiver 16 and by the timer 18 at the point ofobtaining the base station identification information correspond to thebase station identification information.

[0044] The base station detector 19 a sends the notification informationto the service provider control station CS10 via the first network NW1.In other words, the base station detector 19 a has a function ofdetecting the base station that belongs to the network other than thefirst network NW1 including the cellular system mobile communicationsnetwork, and communicating information indicating a detected state ofthe base station to the service provider control station CS10.

[0045]FIG. 3 is a block diagram showing a configuration of the serviceprovider control station CS10.

[0046] As shown in FIG. 3, the service provider control station CS10includes a network interface 21, an input/output section 22, a timer 23,a data base 24 and a processor 25.

[0047] The network interface 21 is connected to the fourth network NW4.The network interface 21 communicates via the fourth network NW4.

[0048] The input/output section 22 includes a display, a key button, amicrophone or a speaker, and performs various kinds of input/outputoperations such as input of user operations and input/output of voices.The input/output section 22 may be individually provided with thevarious kinds of devices mentioned above or may be configured byintegrating these devices in one unit.

[0049] The timer 23 generates date and time information indicating thecurrent date and time.

[0050] The data base 24 stores various kinds of data for grasping theservice areas provided by the second and third networks NW2 and NW3. Inorder to store such various kinds of data, a base station informationtable 24 a, a service area table 24 b and a service contents table 24 care set in the data base 24.

[0051] Here, the base station information table 24 a stores thenotification information sent from the mobile communications terminalMT. The service area table 24 b stores service area informationindicating the extent of the service areas. The service contents table24 c stores information indicating contents of the services provided bythe base stations BS2 and BS3 belonging to the second and third networksNW2 and NW3.

[0052] The processor 25 is configured by use of a microprocessor, forexample. The processor 25 performs various kinds of processing forgenerally managing the service provider control station CS10. Theprocessor 25 comprises a base station information collector 25 a, aservice area calculator 25 b and an area information provider 25 c.

[0053] Here, the base station information collector 25 a storesinformation, which is included in the notification information sent fromthe mobile communications terminal MT and received by the networkinterface 21, in the base station information table 24 a. The servicearea calculator 25 b calculates the service area of each base station byreference to the base station information table 24 a. The areainformation provider 25 c obtains, via the network interface 21,requirement information for provision of the information sent from themobile communications terminal MT. The area information provider 25 cgenerates area information on the above calculated service areaconsidering the requirement information. The area information provider25 c also sends the area information to the mobile communicationsterminal MT which is a transmission source of the requirementinformation. In other words, the area information provider 25 c providesthe area information to the mobile communications terminal MT inaccordance with the requirement from the mobile communications terminalMT.

[0054] Next, an operation in the present embodiment will be described.

[0055] First, the mobile communications terminal MT can basicallyreceive services such as a voice communication, data transmission andsoftware distribution if it can be connected to the control stationsCS1, CS2 and CS3. It is assumed that the mobile communications terminalMT has completed at least procedures such as a contract with the firstnetwork NW1 in order to receive the services mentioned above.

[0056] The processor 19 of the mobile communications terminal MTexecutes base station detection processing shown in FIG. 4 as a functionof the base station detector 19 a at predetermined moments. Thepredetermined moments are moments at predetermined time intervals ormoments when the mobile communications terminal MT moves for a certaindistance, for example. In addition, the base station detectionprocessing may be executed exclusively when the mobile communicationsterminal MT is not communicating.

[0057] In step ST1, the processor 19 uses the second transceiver 15 totry obtaining the base station identification information. Then, if thebase station has supplied the base station identification information,the processor 19 obtains this supplied base station identificationinformation via the second transceiver 15. Alternatively, the processor19 tries communicating with the base station, and obtains via the secondtransceiver 15 the base station identification information communicatedby the base station in a procedure for communication connection.

[0058] The base station available for communication might belong to anetwork with which the mobile communications terminal MT has not made acontract. In this case, the mobile communications terminal MT can notperform an actual communication, but the processor 19 can obtain thebase station identification information since the base stationcommunicates the base station identification information in a processprior to authenticating the mobile communications terminal MT in manycases. In addition, a MAC (media access control) address uniquely givento the base station is utilized as the base station identificationinformation, for example. In addition to this, an IP (Internet protocol)address can also be utilized. A plurality of adjacent base stationscould be covered since the IP address has its layer positioned higherthan a MAC layer. This is effective in calculating the area as a basestation group. In other words, when a plurality of base stationsprovides one service area, the IP address is used to enable detectionper service area.

[0059] Subsequently, the processor 19 determines whether or not the basestation identification information has been obtained successfully, instep ST2. If the base station identification information has beenobtained successfully in this step ST2, the processor 19 generates thenotification information in step ST3. The notification informationgenerated by the processor 19 includes the base station identificationinformation obtained in this step ST1, the positional information, andthe date and time information generated by the GPS receiver 16 and bythe timer 18 at the point of obtaining the base station identificationinformation. In other words, the notification information is informationindicating the base station identification information, the positionwhere the base station identification information is obtained and thedate and time when the base station identification information isobtained.

[0060] The processor 19 accesses the service provider control stationCS10 via the first network NW1 in step ST4. The processor 19 then sendsthe notification information to the service provider control stationCS10 via the first network NW1 in step ST5.

[0061] The processor 19 finishes the base station detection processingif it has completed the transmission of the notification information. Ifthe processor 19 confirms that the base station identificationinformation has not been obtained successfully in this step ST2, itfinishes the base station detection processing without performing thestep ST3 to step ST5.

[0062] In this way, when the mobile communications terminal MT is in astate capable of communicating with the base station BS2, for example,the base station identification information sent from the base stationBS2 is received by the mobile communications terminal MT as shown inFIG. 5 (showing how the mobile communications terminal MT obtains thebase station identification information and sends the notificationinformation including the base station identification information to theservice provider control station CS10). The mobile communicationsterminal MT then sends the notification information including thereceived base station identification information to the service providercontrol station CS10 via the first network NW1 that is different fromthe second network to which the base station BS2 belongs. Therefore, themobile communications terminal MT does not need to have a right toperform a communication via the second network NW2 to which the basestation BS2 belongs.

[0063] When the notification information is sent from the mobilecommunications terminal MT to the service provider control station CS10as described above, the processor 25 of the service provider controlstation CS10 accordingly executes base station information storingprocessing as shown in FIG. 6.

[0064] The processor 25 receives the notification information sent fromthe mobile communications terminal MT as described above via the networkinterface 21 in step ST11. In step ST12, the processor 25 determineswhether or not the base station identification information included inthe notification information has been registered on the base stationinformation table 24 a. The base station identification information,which is included in the notification information received in the past,is registered on the base station information table 24 a as shown inFIG. 7 (a drawing which shows stored information of the base stationinformation table 24 a in FIG. 3), and correspondingly to this, thepositional information and the date and time information are stored.

[0065] If the base station identification information included in thenotification information that has been received this time has not yetbeen registered, the processor 25 registers this base stationidentification information on the base station information table 24 a instep ST13. If the base station identification information included inthe notification information that has been received this time hasalready been registered, the processor 25 passes over the processing ofstep ST13.

[0066] Subsequently, the processor 25 stores the positional informationand the date and time information, which are included in thenotification information received this time, in the base stationinformation table 24 a so that they correspond to the base stationidentification information, in step ST14. With this, the processor 25finishes the base station information storing processing.

[0067] This base station information storing processing is executedevery time the notification information is sent from the mobilecommunications terminal MT. As a result, the base station identificationinformation and the information on the position where, and the date andtime when the base station identification information is obtained arestored in the base station information table 24 a.

[0068] Next, FIG. 8 will be used to describe service area calculationprocessing.

[0069] In the service provider control station CS10, the processor 25executes the service area calculation processing shown in FIG. 8 as afunction of the service area calculator 25 b at every predeterminedmoments. The predetermined moments are moments at predetermined timeintervals or moments when the above-described base station informationstoring processing is finished, for example.

[0070] In step ST21, the processor 25 selects one piece of base stationidentification information, for which the service area has not yet beencalculated in this time of service area calculation processing, from thebase station identification information registered on the base stationinformation table 24 a. In step ST22, the processor 25 calculates theservice area of the base station having the selected base stationidentification information, by reference to the base station informationtable 24 a. In other words, the processor 25 calculates the service areaconsidering the positional information and the date and time informationstored in the base station information table 24 a so that theycorrespond to the selected base station identification information.

[0071] The service area is calculated based on positional distributionwhich is indicated by the positional information corresponding to theselected base station identification information. In FIG. 9 (showing aspecific example of service area calculation), positions that areindicated by the positional information corresponding to the basestation identification information possessed by a base station BSx arerepresented by “x”. The service area is calculated as an area includingall these positions. Various kinds of known methods can be conceived foran algorithm to decide an outer edge of the service area, but anyalgorithm may be adopted as long as those methods are used in a unifiedmanner. This algorithm does not form essential portion of the presentinvention and will not be described in detail.

[0072] Furthermore, various kinds of methods can be conceived as aselection method of the positional information used to calculate theservice area, but any method may be adopted also in this case as long asthose methods are used in a unified manner.

[0073] For example, without considering the date and time information,the service area is conceivably calculated in consideration of thepositions indicated by the positional information corresponding to onepiece of base station identification information. In this case, thenumber of samples is increased, so that highly accurate calculation canbe achieved.

[0074] Alternatively, the service area is conceivably calculatedconsidering only the position indicated by the positional information towhich the date and time information indicating the date and time withina predetermined period correspond, for example. By considering only theposition indicated by the positional information to which the date andtime information indicating the date and time within a certain mostrecent period correspond, it is possible to cope with a case where theservice area is changed due to changes of buildings or vegetation on aperiphery of the base station, and always possible to calculate theservice area in line with current conditions.

[0075]FIG. 10 is a view showing how the service area is thusrecalculated. In FIG. 10, symbols surrounding “x” with “O” are thepositions indicated by the positional information which is newlycollected after the service area shown in FIG. 9 has been calculated.Further, in FIG. 10, symbols “x” indicated by broken lines are thepositions indicated by the older positional information which has beencollected before the predetermined most recent period. By removing theolder positions and calculating the service area considering the newpositions, the service area different from that shown in FIG. 9 iscalculated as shown in FIG. 10.

[0076] If the service area can be calculated as described above, theprocessor 25 updates the service area table so that information on thenewly calculated service area is reflected, in step ST23. Subsequently,in step ST24, the processor 25 determines whether or not the basestation identification information for which the service area has notyet been calculated is left on the base station information table, andthe processor 25 repeatedly executes the processing of the step ST21 tostep ST24 until the service area calculation is finished for all thebase station identification information. The processor 25 therebycalculates the service areas for all the base station identificationinformation registered on the base station information table 24 a. If itcan be confirmed in step ST24 that the service areas have beencalculated for all the base station identification information, theprocessor 25 thus finishes the service area calculation processing.

[0077] Incidentally, the service provider control station CS10 utilizes,for example, a WWW (World Wide Web) technique to accept requests forinformation provision from the mobile communications terminal MT. Ifpredetermined requirement information is sent from the mobilecommunications terminal MT and received by the network interface 21, theprocessor 25 executes area information providing processing shown inFIG. 11 as a function of the area information provider 25 c.

[0078] In step ST31, the processor 25 generates the area information.The area information includes information indicating the extent of theservice area of the base station to be selected, based on at least theinformation stored in the base station information table 24 a. Specificcontents of the area information may be optional, and several specificexamples will be given below.

[0079] (1) Neighborhood Search

[0080] When the received requirement information requires neighborhoodsearch, the requirement information includes the positional information.The processor 25 extracts the information on the service area existingin the vicinity of the position indicated by the positional informationfrom the service area table 24 b. Then, the area information thatincludes information indicating the extent of the service area iscreated. At this moment, if contents of the service are written on theservice contents table 24 c with regard to the base stationidentification information corresponding to the extracted service area,information on the contents of the service may also be contained in thearea information. It should be noted that the contents of the serviceprovided by the base station have been written in advance on the servicecontents table 24 c so that they correspond to the base stationidentification information as shown in FIG. 12 (a drawing showing thestored information of the service contents table 24 c).

[0081] Therefore, the current position of the mobile communicationsterminal MT, which is the transmission source, can be recognized basedon such area information. In addition, it is possible to recognize theextent of the service area existing in the vicinity of a positionspecified by the user. Further, with the information on the contents ofthe service, the contents of the service provided in each service areacan be recognized.

[0082] (2) Service Search

[0083] If the received requirement information requires service search,the requirement information includes service kind information to specifythe service. The processor 25 extracts the base station identificationinformation corresponding to the service specified by the service kindinformation by reference to the service contents table 24 c. Theprocessor 25 then extracts information on the service area concerningthe extracted base station identification information from the servicearea table 24 b, and creates the area information including informationindicating the extent of the service area thereof.

[0084] Therefore, in accordance with such area information, it ispossible to know where the desired service can be provided.

[0085] If the area information is created as described above, theprocessor 25 next sends the area information to the mobilecommunications terminal MT, which is the transmission source, in stepST32. The processor 25 then finishes the area information providingprocessing.

[0086] The user of the mobile communications terminal MT is able to knowvarious kinds of information on the service area in accordance with thearea information as described above. Therefore, based on thisinformation, the user can readily receive the services provided by thesecond network NW2 and the third network NW3.

[0087] Furthermore, the user of the mobile communications terminal MT isable to recognize the information on the service area provided by thesecond network NW2 and the third network NW3 before making contractswith them, so that it is possible to select a network useful to the userbeforehand.

[0088] As described above, the service provider control station CS10 cancalculate and grasp the service areas provided by the second network NW2and the third network NW3 according to the present embodiment.Furthermore, according to the present embodiment, the service areainformation grasp by the service provider control station CS10 can beprovided to the mobile communications terminal MT, so as to let the userof the mobile communications terminal MT know the service conditions inthe second network NW2 and the third network NW3. In addition, theservice provider control station CS10 can operate independently fromboth of the second network NW2 and the third network NW3, so that theabove-mentioned services can be provided by a provider which is notconcerned with the providers of the second network NW2 and the thirdnetwork NW3.

[0089] In addition, it is effective for the providers of the networks inefficiently providing the service contents if the user of the mobilecommunications terminal MT utilizes each network after knowing theservice conditions in each network.

[0090] Furthermore, according to the present embodiment, a wide wirelesssystem such as the mobile telephone network is used for the firstnetwork NW1 which is used by the service provider control station CS10to collect the base station information from the mobile communicationsterminal MT. The wireless system of this kind is generally highlyreliable, so that the base station information can be reliablycollected.

[0091] Still further, according to the present embodiment, the servicearea calculation processing is executed by the service provider controlstation CS10 after the base station information storing processing hasbeen finished, thereby making it possible to always keep the informationof the service area table 24 b up-to-date.

[0092] In addition, the present invention is not limited to theembodiment described above. For example, the current position of themobile communications terminal MT can also be detected based onreceiving conditions of radio waves arriving from the base station. Morespecifically, a distance from each base station can be detected bymeasuring a reception level or the like of the radio waves from the basestation, and the current position of the mobile communications terminalMT can be detected by comparing spaced distances with respect to aplurality of base stations. In this case, the positions of therespective base stations need to be known, but the positions can bedetected with a simple configuration for only measuring the receptionlevel.

[0093] Furthermore, it is possible to know a direction in which theradio waves are coming by providing the mobile communications terminalMT with a plurality of antennas and comparing the radio waves receivedby the respective antennas. As a simple method for this, a method isknown which uses a phase difference of the radio waves. A superresolution method such as MUSIC (Multiple Signal Classification) bysignal processing is known as a more accurate method. Further, thecurrent position of the mobile communications terminal MT can bedetected by recognizing the coming direction of the radio waves from aplurality of base stations (including satellites). In this case, aplurality of antennas and a circuit to compare the radio waves receivedby the antennas are necessary, but the positions of the base stations donot have to be known, thus allowing for high flexibility.

[0094] Still further, if the two methods mentioned above are combined tomeasure distances to the base stations and the directions of the basestations, the current position of the mobile communications terminal MTcan be detected even when one base station transmits the radio waves tobe received.

[0095] Further yet, the base station measures the current position ofthe mobile communications terminal MT, and the base station communicatesthe positional information to the mobile communications terminal MT. Themobile communications terminal MT can also detect its current positionby receiving the positional information communicated by the basestation. Also, the base station can directly notify the service providercontrol station CS10 of the current position of the mobilecommunications terminal MT measured by the base station as describedabove. However, in this case, a structure is provided to synchronize thenotification of the position with the provision of the base stationidentification information from the mobile communications terminal MT tothe service provider control station CS10. Further, as a method ofdetecting the current position of the mobile communications terminal MTby the base station, such a method is conceivable that measures a levelof the radio waves emitted by the mobile communications terminal MT inthe base station and computes a distance between the base station andthe mobile communications terminal MT from the measurements. Moreover,it is also possible to conceive a method in which a plurality ofantennas are provided in the base station for detection by the signalprocessing such as MUSIC mentioned above. In this way, the position ofthe mobile communications terminal MT is detected by the base station,so that the mobile communications terminal MT does not need to comprisea configuration for position detection, which is convenient to a sizereduction of the mobile communications terminal MT, lower powerconsumption, lower costs and the like.

[0096] Further yet, the configuration of the network to be used in notlimited to the embodiment described above. For example, any number ofnetworks can be provided except for the first network NW1 and the fourthnetwork NW4 that are different. The present invention can be utilizedeven in a situation where the service areas of the base stationsoverlap. In this case, it is assumed that the mobile communicationsterminal MT can simultaneously obtain the base station identificationinformation owned by a plurality of base stations, but the notificationinformation including the base station identification information of theplurality of base stations may be transmitted to the service providercontrol station CS10.

[0097] Further yet, as long as the service provider control station CS10can obtain information on congestion and accounting states in each basestation from each network, such information can also be contained in thearea information. In this way, the user can select the service areawhich allows the smoothest communication and which can provide theservices at the least cost.

[0098] Further yet, the service provider control station CS10 maycalculate the service area without considering the date and timeinformation at all. In this case, the mobile communications terminal MTdoes not need to include the date and time information in thenotification information.

[0099] The area information may be provided not only to the mobilecommunications terminal MT but also to the mobile communicationsterminal without base station detection function. Alternatively, thearea information may be provided to non-mobile terminals such aspersonal computers.

[0100] In addition to the above, various modifications can beimplemented without departing from the spirit of the present invention.

[0101] Additional advantages and modifications will readily occur tothose skilled in the art. Therefore, the invention in its broaderaspects is not limited to the specific details and representativeembodiments shown and described herein. Accordingly, variousmodifications may be made without departing from the spirit or scope ofthe general invention concept as defined by the appended claims andtheir equivalents.

What is claimed is:
 1. A mobile communications terminal adapted tocommunicate with a service area calculation apparatus via a first mobilecommunication network, the service area calculation apparatus collectingand transmitting information concerning a service area provided by thefirst mobile communication network and a second mobile communicationnetwork including a base station, the mobile communications terminalcomprising: a positional information generator configured to generatepositional information indicating a current position of the terminal; areceiver which receives identification information sent from the basestation of the second mobile communication network; a notificationinformation generator configured to generate notification informationincluding the identification information and the positional informationgenerated at the time of receiving the identification information; and atransmitter which transmits the notification information to the servicearea calculation apparatus via the first mobile communication network toderive the information concerning the service area.
 2. The mobilecommunications terminal according to claim 1, further comprising a timeinformation generator configured to generate time information indicatinga current time; wherein the notification information generator generatesnotification information further including time information generated atthe time of receiving the identification information.
 3. The mobilecommunications terminal according to claim 1, wherein the positioninformation generator generates the positional information based on atleast one of a GPS (global positioning system) signal, a reception stateof each of signals transmitted from a plurality of different basestations, a declination of signals received by a plurality of differentantennas, and a position of the base station.
 4. The mobilecommunications terminal according to claim 1, wherein the receiverreceives at least one of a MAC (media access control) address and an IP(internet protocol) address as the identification information.
 5. Aservice area calculations apparatus comprising: a receiver whichreceives the notification information transmitted from the mobilecommunications terminal according to claim 1 via the first mobilecommunication network; a storage device which stores a table indicatingthe positional information and the identification information associatedwith each other; and a calculation device configured to calculate aservice area of the base station indicated by the identificationinformation based on a distribution of a position indicated by thepositional information in correspondence with the identificationinformation referring to the table.
 6. The service area calculationapparatus according to claim 5, wherein the storage device stores thetable indicating the positional information, the identificationinformation and time information associated with the positionalinformation and the identification information, when the notificationinformation includes the time information; and the calculation devicecalculates the service area of the base station indicated by theidentification information in a given period, based on the distributionof the position indicated by the positional information for each pieceof the identification information in correspondence with the timeinformation indicating a time within the period referring to the table.7. The service area calculation apparatus according to claim 5, furthercomprising: a service area information generator configured to generateservice area information indicating a range of service area calculated,a second receiver which receives requirement information sent from themobile communications terminal, to generate a reception result; and atransmitter which transmits the service area information to the mobilecommunications terminal which has sent the requirement information viathe mobile communication network, in accordance with the receptionresult.
 8. The service area calculation apparatus according to claim 7,wherein the transmitter transmits only the service area information onthe service area satisfying a preset condition to a position indicatedby the positional information, when the requirement information includesthe positional information.
 9. The service area calculation apparatusaccording to claim 7, further comprising: a memory device configured tostore service information indicating service contents provided by thebase station of the mobile communications network, and corresponding tothe identification information; wherein the generator reads the serviceinformation corresponding to the identification information of thecalculated service area from the memory device, and generates theservice area information including the service information.
 10. Theapparatus according to claim 5, wherein the calculation devicecalculates the service area of the base station indicated by theidentification information included by notification information which isnewly received.
 11. A method of calculating a service area, comprising:receiving notification information including identification informationof a base station and positional information of the mobilecommunications terminal, the notification information being sent fromthe mobile communications terminal via a mobile communications network;storing a table indicating the identification information and thepositional information included in the received notification informationand corresponding to the identification information; examining adistribution of positions indicated by the positional information foreach piece of identification information referring to the table; andcalculating a service area of the base station indicated by theidentification information based on the distribution.
 12. The methodaccording to claim 11, wherein the storing includes storing the tableindicating the positional information, the identification informationand time information associated with the positional information and theidentification information, when the notification information includesthe time information; and the calculating includes calculating theservice area of the base station indicated by the identificationinformation in a given period, based on the distribution of the positionindicated by the positional information for each piece of theidentification information in correspondence with the time informationindicating a time within the period referring to the table.
 13. Themethod according to claim 11, further comprising: generating servicearea information indicating a range of service area calculated,receiving requirement information sent from the mobile communicationsterminal, to generate a reception result; and transmitting the servicearea information to the mobile communications terminal which has sentthe requirement information via the mobile communication network, inaccordance with the reception result.
 14. The method according to claim13, wherein the transmitting includes transmitting only the service areainformation on the service area satisfying a preset condition to aposition indicated by the positional information, when the requirementinformation includes the positional information.
 15. The methodaccording to claim 13, further comprising: storing service informationindicating service contents provided by the base station of the mobilecommunications network, and corresponding to the identificationinformation; wherein the generating includes reading the serviceinformation corresponding to the identification information of thecalculated service area, and generating the service area informationincluding the service information.
 16. The method according to claim 11,wherein the calculating includes calculating the service area of thebase station indicated by the identification information included bynotification information which is newly received.